The work in progress is an investigation of whether the capsule of the salivary gland plays a role in regulating the repair process following the removal of a portion of the parenchyma from the submandibular or parotid glands. Preliminary observations in the rat and the dog suggest that extirpation of some parenchyma is not followed by scarring but that repair occurs in adults of both species. In rats particularly, it has been noted that local hemorrhage is often followed by atrophy. Therefore, careful surgical and pharmaceutical measures to control hemorrhage are essential. These are in progress and, if successful, will be followed by autoradiography using tritiated thymidine to follow the sequential changes occurring during the healing process. The possibility of a sex difference in the susceptibility of the rat to salivary gland atrophy following surgery will be investigated as will be the possible relationship between capsular topography an the extent of repair.